1. Field of the Invention
The present invention relates to fasteners for pinning metal sheets or similar plates together.
When preparing the final assembly of metal sheets, for example by riveting, a temporary assembly of said metal sheets is generally formed by means of pinning fasteners passing through facing holes formed therein.
2. Description of the Prior Art
Such metal sheet pinning fasteners are described for example in the French patent FR-A-789 945 of May 13th 1935, in its Certificate of Addition FR-A-48 048 of May 13th 1936 or else in the French patent FR-A-1 492 310 of 8th July 1966.
Known pinning fasteners comprise:
a bearing face intended to come into contact with the external face of one of said external metal sheets of the metal sheet assembly,
at least one elongate element intended to pass through facing holes formed in the metal sheets of said assembly and having an engagement nose, and
a mechanism for generating a relative movement, in the longitudinal direction, between said elongate element and said bearing face and, possibly, a transverse movement of said engagement nose so that said metal sheets may be pressed between said bearing face and said engagement nose, which is then engaged behind the external face of the other external metal sheet of the assembly, at the edge of the corresponding hole.
Generally, in these known pinning fasteners, said bearing face is the front face of a body through which a threaded rod passes longitudinally bearing said elongate element at its end passing through said front face, whereas said mechanism comprises a nut mounted on the threaded rod, outside said body on the side opposite said front face thereof, a pressure spring being mounted imprisoned on said threaded rod between said nut and said body.
Thus, in these known fasteners, said mechanism which is essentially formed of said threaded rod and said nut projects from the side opposite said elongate element. The result is then that the longitudinal dimension of said fasteners is appreciable. Since, in addition, the length of said threaded rod externally of said body corresponds to the thickness of the assembly of metal sheets to be assembled together, it can be seen that the fasteners provided for thick assemblies are very long.
Thus, very often, for reasons of available space, it is impossible to use pinning fasteners for thick assemblies and the temporary assembly must be formed by means of screws, nuts and washers. When the assembly of metal sheets is not accessible, simultaneously, from both sides by the same operator, which is for example the case when the wings of an aircraft are assembled to the fuselage thereof, two operators are then needed, respectively on each side of the assembly and forming said assembly by means of bolts and nuts.